The overall objective of this project is to advance our understanding of the peripheral mechanisms underlying the motor control of speech production in both normal individuals and those with neurological disturbances by identifying and elucidating basic neuromotor and biomechanical properties of the speech production system. The research is motivated by a perceived need for understanding the peripheral mechanisms and first and second order properties of these mechanisms as a prerequisite to the formulation of models that explain how the central nervous system produces and controls speech gestures. The proposed research is derived from empirical questions concerning the peripheral representation of central processes, the neuromotor encoding of articulatory movements, and the biomechanical properties of the orofacial system relevant to speech production. These questions are studies by examining system level responses to experimentally induced perturbations in afferent and efferent pathways. The responses are measured at the muscle activity, movement, and acoustic levels and are processed using a digital computer. Interactive computer programs enable on-line editing and graphical and statistical analyses of multi-channel electromyographic, multi-dimensional movement, and acoustic measurements.